A study of hybrid control algorithms for buck-boost converter based on fixed switching frequency

Buck-boost converter is a typical hybrid dynamic system including both discrete and continuous subsystems which may be modeled by a simple formal model named hybrid automaton. Based on the hybrid automaton model, this paper proposes a new hybrid control algorithm of buck-boost converter, which can simultaneously work in CCM and DCM operations. Using this control algorithm, the control design is simplified to a selection of transition guards between different operation statuses. Unlike other hybrid control algorithms, the switching frequency at steady state does not vary with the disturbances of load and input voltage in the entire work process. The simulation results show that this algorithm has the advantages of simple algorithm, fast dynamic response and high stable precision, and can be further extended to other power electronic converters.